“…Another natural path toward further improvement would be to employ the recently developed theory and testing procedures from Kneip et al (2015;. The third natural direction of future research would be to employ alternative methods of estimating efficiency, such as ‗Imprecise DEA', ‗Context-Dependent Assurance Region DEA', or DEA with non-homogeneous firms (see Zhu, 2004;Cook et al, 2006;Cook and Zhu, 2008), Stochastic DEA (Simar and Zelenyuk, 2011) as well as alternative methods to analyse the influence of factors on efficiency, as based on recent work by Bădin et al (2010), Bădin et al (2012), Daraio and Simar (2014), Mastromarco and Simar (2015), Tzeremes (2015) and Matousek and Tzeremes (2016), Park et al (2015), Simar et al (2017) among others. Finally, application of all these methods to larger or different data sets would also be interesting.…”